into the Cause of Voltaic Electricity, 



293 



and chemical,) effects, there is a limit in the number of pairs 

 which produces them with the greatest degree of intensity. 



II. That the number of pairs which in each case produces 

 the maximum of effect, diminishes in proportion as the body 

 placed between the poles is a better conductor, and the liquid 

 interposed between the poles a worse one, and less adapted to 

 exert a lively chemical action. 



III. That it often happens, especially when the pile is not 

 very energetic, that when the number of pairs the most fa- 

 vourable to the production of a certain effect, in each case, 

 has been exceeded, the diminution in the intensity of the effect 

 which results from the addition of other pairs, ceases when 

 this addition amounts to a certain number; that the effect then 

 again becomes as intense as it was previously, to diminish a 

 second time in the same manner by again increasing the num- 

 ber of pairs. 



IV. That whatever be the absolute intensity of the effects 

 produced by a pile, this intensity diminishes with a rapidity 

 proportional to the amount of the number of the pairs com- 

 posing the pile, such at least is the fact when the conductor 

 placed between its poles is very good, and the liquid with 

 which it is charged exerts a feeble chemical action. 



As the preceding results are entirely new I shall describe 

 some of the experiments by which they were arrived at. 



Exp. I. — Pairs of zinc and copper, with surfaces four inches 

 square charged with slightly acidulated water. 



Number of Degrees of 



Pairs. Breguet's helix. 



20 65° 



15 

 10 

 5 

 3 

 2 

 1 



50 

 40 

 40 

 43 

 35 

 25 



Exp. II. — Pairs of zinc and copper, with surfaces sixteen 

 inches square charged with acidulated water which has been 

 several times employed, and which consequently is more saline 

 than acid. 



